Excision margins for melanoma in situ on the head and neck—A single-center 10-year retrospective review of treatment with Mohs micrographic surgery

Background: Although current guidelines recommend a 5 mm surgical margin for the excision of melanoma in situ (MIS), increasing evidence has shown this may be suboptimal to achieve tumor clearance. Objective: To evaluate margins required for optimal cure rates with excision of MIS on the head and neck and investigate tumor and/or patient factors in those requiring >5 mm margins to achieve tumor clearance. Methods: A retrospective chart review was performed on 846 (807 primary and 39 recurrent) MIS cases on the head and neck treated in the authors’ dermatologic surgery department over a 126-month (10.5 year) period. Results: Sixty-two percent were cleared with 5 mm margins. A total of 15 mm margins were required to achieve a 97% clearance rate. Difference in clearance rate between margin thresholds was significant (P <.001). Tumor location on the cheek and larger preoperative size correlated with requiring >5 mm margins to achieve tumor clearance (P =.006 and P =.001, respectively). Limitations: This is a single-center retrospective study which relies on accurate documentation of clinical data. Conclusion: This study demonstrates that MIS on the head and neck often requires margins >5 mm margins to achieve tumor clearance. When Mohs micrographic surgery is not possible, excision margins of ≥10 mm are likely necessary for head and neck tumors.